saving iphoto to iomega drive

[mcsmcs]

I am not a techy person so I don't know if I will explain this properly but....I am trying to back up iPhoto library to my iomega drive from my mac. A few days later, when I go to update again, the iPhoto that I open on my drive already seems to have the pictures that I've since added to my mac and therefore, not yet put on the drive. How is this possible?
Are my pix on the drive?? How can I check that they are there?

 

[Spawn_Dooley]

What method are you using to back up your iPhoto Library?

 

[mcsmcs]

Hi, I'm going into the pictures folder and dragging iphoto library across.....